Some Barclays customers were hit by a technical problem over the weekend which stopped them making payments.
The problem began on Saturday and continued into today because of routine maintenance that was taking place with the clocks going back.
A Barclays spokeswoman said: "We can confirm that customer services are now recovering from the outage we experienced yesterday. We apologise to customers for any inconvenience caused."
She said the scheduled outage yesterday meant systems took slightly longer to come back on this morning.
She confirmed that the issues were internal and were not caused by a cyber attack.
Police have been investigating an attack on telecoms giant TalkTalk which may have resulted in the theft of millions of customers' bank and credit card details.
Data stolen does not allow criminals to plunder customers' bank accounts, TalkTalk has said.